Method of controlling alternating current plasma display panel for improving data write-in characteristics without sacrifice of durability

ABSTRACT

An alternating current plasma display panel selectively fires pixels for producing an image on a display area, a controlling method firstly supplies a negative sustain pulse to the scanning electrodes and the sustain electrodes so as to keep selected pixels fired and, thereafter, a positive sustain pulse to either scanning or sustain electrodes for putting the selected pixels into ready for perfectly erasing state, and pixels to be fired in the next field are surely selected from the perfectly erased pixels.

FIELD OF THE INVENTION

This invention relates to an alternating current plasma display paneland, more particularly, to a method of controlling an alternatingcurrent plasma display panel for improving data write-in characteristicswithout sacrifice of durability.

DESCRIPTION OF THE RELATED ART

The plasma display panel has various attractive features such as aself-light emitting thin structure, a prompt response and a wide screenfor producing a full-color large contrast image without flicker. Thesefeatures are desirable for an interface between a computer and anoperator and a full-color image production.

The plasma display panel is broken down into two categories. The firstcategory is called as an alternating current plasma display panel. Inthe alternating current plasma display panel, electrodes are coveredwith dielectric layers, and alternating discharge indirectly takes placein the discharging space between the dielectric layers. The secondcategory is called as a direct current plasma display panel. The directcurrent plasma display panel has electrodes exposed to the dischargingspace, and produces direct discharge

The alternating current plasma display panel is further broken down intotwo sub-categories, i.e., a pulse memory driving type alternatingcurrent plasma display panel and a refresh type alternating currentplasma display panel. The pixels of the pulse memory driving typealternating current plasma display panel have a kind of memory function,and the pulse memory driving type alternating current plasma displaypanel previously memorizes the selection in the pixels to be dischargedbefore formation of a picture. The refresh type alternating currentplasma display panel does not use the memory function. The brightness ofthe alternating current plasma display panel is proportional to thenumber of discharges or the repetition of pulse applied to theelectrodes. However, when the display area is increased, the refreshtype alternating current plasma display panel decreases theluminescence, and, for this reason, is appropriate for a small imagedisplay.

FIG. 1 illustrates the structure of a pixel incorporated in a typicalexample of the pixel incorporated in the prior art pulse memory drivingtype alternating current plasma display panel. The pixel largelycomprises a back substrate structure 1 and a front substrate structure2, and a partition wall 3 spaces the back substrate structure 1 from thefront substrate 2. Discharging gas 4 such as helium, neon, xenon orgaseous mixture thereof fills the space between the back substratestructure 1 and the front substrate structure 2. The discharging gasemits ultra-violet light.

The back substrate structure 1 includes a transparent glass plate 1a,and a data electrode 1b is formed on the transparent glass plate 1a. Thedata electrode 1b is covered with a dielectric layer 1c, and a phosphorlayer 1d is laminated on the dielectric layer 1c. The ultra-violet lightis radiated onto the phosphor layer 1d, and the phosphor layer 1dconverts the ultra-violet light to visible light. The visible light isradiated as indicated by arrow AR1.

The front substrate structure 2 includes a transparent glass plate 2a,and a scanning electrode 2b and a sustain electrode 2c are formed on thetransparent glass plate 2a. The scanning electrode 2b and the sustainelectrode 2c extend in the perpendicular direction to the data electrode1b. Tracing electrodes 2d/2e are laminated on the scanning electrode 2band the sustain electrode 2c, respectively, and are operative to reducethe resistance against a scanning pulse signal and a sustain pulsesignal. These electrodes 2b, 2c, 2d and 2e are covered with a dielectriclayer 2f, and the dielectric layer 2f is overlain by a protective layer2g. The protective layer 2g is formed of magnesium oxide, and preventsthe dielectric layer 2f from the discharge.

The prior art pixel shown in FIG. 1 produces a piece of image asfollows. Firstly, an initial pulse is applied between the scanningelectrode 2b and the data electrode 1b, and is larger than thedischarging threshold. Discharge takes place through the discharging gas4. Positive charge and negative charge are attracted toward thedielectric layers 2f/1c over the scanning electrode 2b and the dataelectrode 1b, and are accumulated thereon as wall charges. The wallcharges produce potential barriers, and gradually decrease the effectivepotential. For this reason, even if the initial pulse is continuouslyapplied between the scanning electrode 2b and the data electrode 1b, theprior art pixel stops the discharge.

Thereafter, a sustain pulse is applied between the scanning electrode 2band the sustain electrode 2c, and is identical in polarity with the wallpotential. The wall potential is superposed on the sustain pulse. Forthis reason, even though the amplitude of the sustain pulse is low, thetotal potential exceeds the discharging threshold, and continues thedischarge. Thus, while the sustain pulse is being applied between thescanning electrode 2b and the sustain electrode 2c, the sustaindischarge is continued. This is the memory function.

When an erase pulse is applied between the scanning pulse 2b and thesustain pulse 2c, the wall potential is canceled, and the pixel stopsthe sustain discharge. The erase pulse is a wide in pulse width and lowin amplitude, or is narrow in pulse width and as low in amplitude as thesustain pulse.

FIG. 2 illustrates the layout of pixels incorporated in the pulse memorydriving type alternating current plasma display panel. The pixel 5 areidentical in structure with the prior art pixel shown in FIG. 1, andform a display area 6. The pixels 5 are arranged in j rows and kcolumns, and a small box stands for each pixel 5 in FIG. 2. Scanningelectrodes Sc1 to Scj and sustain electrodes Su1 to Suj extend in thedirection of rows, and the scanning electrodes Sc1 to Scj arerespectively paired with the sustain electrodes Su1 to Suj. The pairs ofscanning/sustain electrodes Sc1/Su1 to Scj/Suj are respectivelyassociated with the rows of pixels 5. On the other hand, data electrodesD1 to Dk extend in the direction of columns, and are associated with thecolumns of pixels 5, respectively.

FIG. 3 illustrates a prior art method of controlling an alternatingcurrent plasma display panel. The prior art method is hereinbelowreferred to as "first prior art controlling method". Priming dischargeperiod A, write-in period B and sustain discharge period C form eachfield, and the prior art alternating current plasma display panelrepeats the field so as to form a picture on the display area 6. Thepriming discharge period A may be deleted from the field.

Active particles and the wall charges are produced in the primingdischarge period A so as to obtain stable write-in dischargecharacteristics. A negative priming discharge pulse Pp is applied to allthe sustain electrode Su1 to Suj, and causes the priming discharge totake place in all the pixel 5. The priming discharge produces the wallcharges. A negative erase pulse Ppe is concurrently supplied to thescanning electrodes Sc1 to Scj, and erases the wall charge undesirablefor write-in discharge and sustain discharge.

In the write-in period B, a negative scanning pulse Pw is sequentiallysupplied to the scanning electrodes Sc1 to Scj, and a positive datapulse Pd is selectively supplied to the data electrodes D1 to Dkassociated with the pixels to be fired in synchronism with the scanningpulse Pw. Then, write-in-discharge takes place in pixels 5 to be fired,and the wall charge is produced for the pixel 5. The photo-emittingcurrent starts to flows at respective timings when both scanning anddata pulses Pw/Pd are applied between the scanning electrodes Sc1 to Scjand the data electrodes D1 to Dk.

In the sustain discharge period C, a negative sustain pulse Pc issupplied to the sustain electrodes Su1 to Suj, and, another negativesustain pulse Ps is supplied to the scanning electrodes Sc1 to Scj. Thenegative sustain pulse Ps is different in phase from the negativesustain pulse Pc by 180 degrees. The negative sustain pulses Pc/Psmaintain the brightness of the pixel 5 selected in the write-in periodB. After application of the last negative sustain pulse Pce, a negativeerase pulse Pse is concurrently supplied to the scanning electrodes Sc1to Scj, and erases the wall charge. As a result, the pixels 5 stops thesustain discharge.

Another prior art controlling method is disclosed by K. Yoshikawa et al.in "A Full Color AC Plasma Display with 256 Gray Scale", JAPAN DISPLAY'92, pages 605 to 608, and FIG. 4 illustrates the prior art controllingmethod disclosed in the paper. The prior art controlling methodhereinbelow is referred to as "second prior art controlling method".Although the authors use different terms in the paper, step 1 to step 3of the address period correspond to the priming discharge period A, andstep 4 of the address period is corresponding to the write-in dischargeperiod B. The sustain discharge period C is referred to as "sustainperiod" in the paper. The data electrodes D1 to Dk, the sustainelectrodes Su1 to Suj and the scanning electrodes Sc1 to Scj arecorresponding to address electrodes AD, sustain electrodes X and sustainelectrodes Y1 to Y480, respectively.

In the priming discharge period A, a positive erase pulse Psec isfirstly applied to the sustain electrodes X, and Erases the wall chargeproduced in the previous field. Subsequently, a positive primingdischarge Ppc is concurrently supplied to the sustain electrodes y1 toY480, and produces two kinds of wall charges through priming discharge.Thereafter, a positive erase pulse Ppec is applied to the sustainelectrodes X, and erases one of the two kinds of wall chargesundesirable for write-in discharge and sustain discharge.

In the write-in discharge period B, the sustain electrodes X are changedto a positive high potential level, and a scan pulse Pw sequentiallychanges the sustain electrodes Y1 to Y480 from a positive potentiallevel to the ground level. A positive address pulse Pd is selectivelyapplied to the address electrodes AD, and the scanning pulse Pw and thepositive address pulse Pd specify pixels 5 to be fired.

In the sustain discharge period C, a positive sustain pulse Psus isperiodically supplied to the sustain electrodes X, and a positivesustain pulse Psue is also periodically supplied to the sustainelectrodes Y1 to Y480. The positive sustain pulse Psus is different fromthe positive sustain Psue by 180 degrees. The positive sustain pulsesPsus/Psue maintain the sustain discharge, and the selected pixels 5 arefired.

As described hereinbefore, the gradation is changed by controlling thenumber of sustain pulses. A sub-field technology is appropriate for highbrightness. FIG. 5 illustrates the sub-field technology for controllingthe gradation. A single field is divided into sub-fields SF1, SF2, SF3,SF4, SF5 and SF6, and a picture is produced through the field. Althoughthe time period for each field is variable depending upon thecomputer/broadcasting system, the field usually ranges from 1/50 secondto 1/75 second. A field is divided into k sub-fields, and k is 6 in theexample shown i FIG. 5.

The sub-field consists of the priming discharge period A, the write-indischarge period B and the sustain discharge period C. In the exampleshown in FIG. 5, only the sub-field SF6 has all the periods A/B/C, andthe priming discharge period A is deleted from the other sub-fields SF5to SF1, because the pixels maintain the effect of the priming dischargeA through the field. However, the priming discharge period A may beinserted in another sub-field.

The brightness Br of each pixel is given by equation 1. ##EQU1## where kis the number of sub-fields incorporated in the field, n is the positionof each sub-field, L1 is the brightness in the darkest sub-field anda_(n) is either 1 or 0. The brightest sub-field has the position n=k ,and the darkest sub-field has the position n-1. When a pixel emits thelight in a sub-field, a_(n) is 1 in the sub-field. On the other hand,when the pixel is not expected to emit the light in another sub-field,a_(n) is changed to zero.

In the example shown in FIG. 5, the field is divided into sixsub-fields, and the sub-field technology achieves 64 gray scale, i.e.,2^(k) =2⁶ =64. If the plasma display is designed to produce a full colorimage, each of the three primary colors has 64 grades, and the prior artalternating current plasma display panel can produce 262144 colors,i.e., 64³. When the field is not divided into a plurality of sub-fields,each of the three primary colors has two grades, i.e., on/off, and theprior air alternating current plasma display panel can produce 8 colors.

The prior art controlling methods repeatedly apply the sustain dischargepulses Pc/Ps and Psus/Psue to the sustain/scanning electrodesSu1-Suj/Sc1-Scj and X/Y1-Y480, and the sustain discharge pulses areeither negative or positive with respect to the potential level on thedata electrodes D1-Dk and AD.

When the sustain discharge pulses have negative large potential withrespect to the potential level on the data electrodes, the ion isattracted toward the protective layer 2g, and the phosphor layer 1d isnot subjected to the ion-bombardment in the sustain discharge period.For this reason, the negative sustain pulses prolong the duration oflife, and improves the durability of the prior art alternating currentplasma display. However, the negative sustain pulses deteriorate thedata write-in characteristics of the prior art alternating currentplasma display panel. In detail, the last sustain pulse is also negativewith respect to the data electrodes, and the erase pulse requires alarge height in the sustain discharge period. The erase pulse with thelarge height causes the negative wall charge to remain over the dataelectrodes, and the negative wall charge reduces the effective potentialof the data pulse Pd and the effective potential of the scanning pulsePw. This results in the deterioration of the data write-incharacteristics.

FIGS. 6A and 6B illustrates the wall charges produced in the sustaindischarge period through the first prior art controlling method. Thepixel is assumed to be controlled through the first prior artcontrolling method. When the last sustain pulse Pce is applied to thesustain electrode 2c, the positive wall charge is induced over thesustain electrode 2c, and the negative wall charge is accumulated underthe sustain electrode 2b and over the data electrode 1b as shown in FIG.6A. The electric force lines 10 are directed from the sustain electrode2c to the scanning electrode 2b and the data electrode 1b. In thissituation, the ion is hardly directed toward the magnesium oxide layer2g under the scanning electrode 2b, and the secondary electron is notemitted. Thus, secondary discharge due to the internal potential hardlytakes place after the application of the last erasing pulse.

Subsequently, the erase pulse Pse is applied to the scanning electrode2b, and the internal potential due to the wall charge is superposedthereon. Then, the erasing discharge takes place between the scanningelectrode 2b and the sustain electrode 2c. However, the secondarydischarge due to the wall charge hardly takes place, and the erase pulserequires large pulse height. After the erasing discharge, the internalpotential between the scanning electrode 2b and the sustain electrode 2cis removed. The erase pulse with the large pulse height induces thenegative wall charge on the phosphor layer 1d over the data electrode 1bas shown in FIG. 6B. Thus, the negative wall charge is left on thephosphor layer 1d over the data electrode 1b after the erasingdischarge. The negative wall charge gives rise to increase the potentialrequired for the data write-in, because the potential due to the datapulse Pd and the scanning pulse Pw is opposite in polarity to theinternal potential due to the negative wall charge.

If the negative wall charge is much, the dispersion of wall chargebetween the pixels is serious, and the data pulse Pd is expected to takeup the dispersion. This results in a higher pulse height, and a datadrive IC controlling data electrodes is expected to withstand the largepotential. However, the withstand voltage is presently of the order of130 volts, and would be damaged. For this reason, it is impossible toincrease the pulse height of the data pulse Pd. The insufficient pulseheight can not make all the pixels to be fired ready for firing state.This means some pixel is not fired. As a result, the prior artalternating current plasma display panel incorrectly produces a pictureon the display area.

The large pulse height is not required for the second prior artcontrolling method. However, the phosphor layer 1d is much liable to bedamaged, and makes the alternating current plasma display panel notdurable. In detail, FIGS. 7A and 7B illustrate the wall charges producedin the sustain discharge period through the second prior art controllingmethod. The positive sustain pulse Psue is finally applied to thescanning electrode 2b in the sustain discharge period. The positivesustain pulse Psue induces the negative wall charge under the scanningelectrode 2b, and the positive wall charge is accumulated under thesustain electrode 2c and over the data electrode 1b as shown in FIG. 7A.The electric force lines are directed toward the scanning electrode 2b,and the magnesium oxide layer 2g is liable to emit the secondaryelectron due to the ion bombardment. Thereafter, the positive erasingpulse Psec is applied to the sustain electrode 2c, and is superposed onthe internal potential due to the wall charges. Then, the erasingdischarge takes place between the scanning electrode 2b and the sustainelectrode 2c. The internal potential due to the wall charges promotesthe erasing discharge, and the erasing pulse Psec has a relatively smallpulse height.

The erasing discharge removes the internal potential between thescanning electrode 2b and the sustain electrode 2c, and only a smallamount of negative wall charge is left over the data electrode 1b asshown in FIG. 7B. The dispersion of wall charge is less than that of thepixels controlled by using the first prior art controlling method, andthe data pulse Pd does not required a large pulse height. For thisreason, the second prior art controlling method is desirable rather thanthe first prior art controlling method.

However, the second controlling method encounters a problem in thedurability of the phosphor layer 1d. The positive sustain pulsesPsus/Psue are respectively applied to the sustain electrode 2c and thescanning electrode 2b, and the data electrode 1b is maintained at theground level. For this reason, the ion is attracted toward the dataelectrode 1b, and the phosphor layer 1d is subjected to ion bombardment.The ion bombardment damages the phosphor layer 1d, and deteriorates it.As a result, the pixel rapidly decreases the brightness, and thealternating current plasma display is not durable.

Thus, there is a trade-off between the data write-in characteristics andthe durability of the alternating current plasma display, and both firstand second prior art controlling methods can not satisfy bothrequirements.

SUMMARY OF THE INVENTION

It is therefore an important object of the present invention to providea method of controlling an alternating current plasma display panelwhich makes the alternating current plasma display panel durable withoutsacrifice of the data write-in characteristics.

To accomplish the object, the present invention proposes to apply asustain pulse positive with respect to data electrodes to either sustainor scanning electrodes after application of a negative sustain pulse.

In accordance with one aspect of the present invention, there isprovided a method of controlling an alternating current plasma displaypanel including a plurality of data electrodes covered with a firstdielectric structure, a plurality of scanning electrodes covered with asecond dielectric structure spaced from the first dielectric structurefor forming a space filled with discharging gas and a plurality ofsustain electrodes covered with the second dielectric structure andrespectively paired with the plurality of scanning electrodes forforming a plurality of electrode pairs, each of the plurality of dataelectrodes and each of the plurality of electrode pairs of defining oneof a plurality of pixels selectively fired, and the method comprises thesteps of a) applying a scanning pulse sequentially to the plurality ofscanning electrodes and a data pulse selectively to the plurality ofdata electrodes so as to create a first internal potential available forfiring in select certain pixels selected from the plurality of pixelsand b) alternately applying a first sustain pulse negative with respectto a potential level on the plurality of data electrodes to theplurality of sustain electrodes and the plurality of scanning electrodesso as to make the certain pixels fired, c) applying a second sustainpulse positive with respect to the potential level on the plurality ofdata electrodes to either sustain or scanning electrodes so as toaccumulate wall charges on the first insulating structure and the secondinsulating structure for creating a second internal potential expressedby a first electric force line directed from the first insulatingstructure to the second insulating structure and a second electric forceline between a first area of the second insulating structure adjacent tothe plurality of scanning electrodes and a second area of the secondinsulating structure adjacent to the plurality of sustain electrodes,and d) erasing the wall charges from the first insulating structure andthe second insulating structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the method will be more clearlyunderstood from the following description taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a cross sectional view showing the structure of the pixel;

FIG. 2 is a plane view showing the layout of the pixels and theassociated electrodes;

FIG. 3 is a timing chart showing the first prior art controlling method;

FIG. 4 is a timing chart showing the second prior art controlling methoddisclosed in the paper entitled as "A Full Color AC Plasma Display with256 Gray Scale";

FIG. 5 is a view showing the sub-field technology for controlling thegradation;

FIGS. 6A and 6B are cross sectional views showing the wall chargesproduced in the pixel during the sustain discharge period through thefirst prior art controlling method;

FIGS. 7A and 7B are cross sectional views showing the wall chargesproduced in the pixel during the sustain discharge period through thesecond prior art controlling method.

FIG. 8 is a timing chart showing a method of controlling an alternatingcurrent plasma display panel according to the present invention;

FIGS. 9A and 9B are cross sectional views showing wall charges producedin a pixel during a sustain discharge period;

FIG. 10 is a timing chart showing a modification of the controllingmethod shown in FIG. 8;

FIG. 11 is a timing chart showing another method of controlling analternating current plasma display panel according to the presentinvention;

FIG. 12 is a timing chart showing yet another method of controlling analternating current plasma display panel according to the presentinvention;

FIG. 13 is a timing chart showing still another method of controlling analternating current plasma display panel according to the presentinvention;

FIG. 14 is a timing chart showing another method of controlling analternating current plasma display panel according to the presentinvention;

FIG. 15 is a timing chart showing another method of controlling analternating current plasma display panel according to the presentinvention;

FIG. 16 is a timing chart showing another method of controlling analternating current plasma display panel according to the presentinvention; and

FIG. 17 is a timing chart showing another method of controlling analternating current plasma display panel according to the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

FIG. 8 illustrates a controlling method embodying the present invention.The controlling method is available for the alternating current plasmadisplay panel shown in FIGS. 1 and 2, and description is concentrated onthe controlling method. However, the references for the electrodes andthe layers are inserted into the following description. In the followingdescription, the polarity is determined with respect to the potentiallevel on the data electrodes 1b/D1-Dk. A single sub-field is shown inFIG. 8, and the sub-field is repeated for producing a picture on thedisplay area 6. However, the priming discharge period A may beselectively deleted from the second to the last sub-fields.

The sub-field shown in FIG. 8 consists of the priming discharge periodA, the write-in discharge period B and the sustain discharge period C.All of the pixels 5 are fired in the priming discharge period A, andpixels 5 to be fired are selected from the pixel array in the write-indischarge period B so as to produce an image on the display area 6. Theselected pixels 5 are continuously fired in the sustain discharge periodC, and the sustain discharge is selectively repeated over the sustaindischarge period C so as to give a gradation to each of the pixels 5.

A negative priming pulse Pp- is supplied to all the sustain electrodesSu1 to Suj between time t1 and t2. The negative priming pulse Pp- hasthe pulse height ranging from 170 volts to 200 volts, and the pulsewidth is between 5 microseconds to 20 microseconds. On the other hand, apositive priming pulse Pp+ is supplied to all the scanning electrodesSc1 to Scj between time t1 and time t2, and the negative priming pulsePp- and the positive priming pulse Pp- are recovered to the ground levelGND at time t2. A negative erasing pulse Ppe follows the positivepriming pulse Pp+. The negative erasing pulse Ppe goes down at time t2,and is recovered to the ground level at time t3. The positive primingpulse Pp+ has the pulse height ranging from 170 volts to 200 volts, andthe pulse width is also between 5 microseconds to 20 microseconds. Thepulse height of the negative erasing pulse Ppe ranges from 50 volts to150 volts, and the pulse width is as narrow as the minimum pulse widthranging from 0.5 microsecond to 2 microseconds. The pulse width of thenegative erasing pulse Ppe preferably ranges from 0.5 microsecond to 2microsecond.

A large potential difference takes place between the sustain electrodesSu1 to Suj and the scanning electrodes Sc1 to Scj, and all the pixels 5are fired when the potential difference exceeds the threshold fordischarge. However, the potential difference between the data electrodesD1-Dk and the sustain/scanning Su1-Suj/Sc1-Scj does not exceed thethreshold, and any discharge does not take place therebetween. Thepriming discharge produces two kinds of wall charges, and creates aninternal potential. The internal potential is superposed on the negativeerasing pulse Ppe, and erasing discharge takes place so as to cancel thewall charge undesirable for the write-in discharge.

Upon completion of the erasing operation, the controlling method entersinto the write-in discharge period B, and the pixels 5 to be fired arespecified through a data write-in. In detail, a negative scanning pulsePw is sequentially supplied to the scanning electrodes Sc1 to Scj, and apositive data pulse Pd is selectively applied to the data electrodes D1to Dk. The negative scanning pulse Pw has the pulse height between 170volts and 200 volts and the pulse width of the order of 3 microseconds.On the other hand, the positive data pulse Pd has the pulse heightbetween 50 volts and 80 volts, and the pulse width is equal to thenegative scanning pulse Pw. The negative scanning pulse Pw and thepositive data pulse Pd specifies the pixels 5 to be fired. If thenegative scanning pulse Pw and the positive data pulse Pd areconcurrently applied to a pixel 5, the pixel 5 is fired. However, if thenegative scanning pulse Pw and the positive data pulse Pd are applied toa pixel 5 at different timings, the pixel 5 is never fired.

In this instance, the negative scanning pulse Pw is applied to thescanning electrode Sc1 between time t4 and time t5, the scanningelectrode Sc2 between time t6 and time t7, the scanning electrode Sc3between time t8 and time t9, . . . and the scanning electrode Scjbetween time t10 and time t11, and the positive data pulse Pd isselectively applied to the data electrodes D1 to Dk between time t4 andtime t5, between time t6 and time t7, between time t8 and time t9, . . .and between time t10 and time t11. If the positive data pulse Pd isapplied to the data electrodes D1 and D2 between time t4 and times t5,only the pixels at the crossing point between the scanning electrode Sc1and the data electrodes D1/D2 are fired.

After time t11, the alternating current plasma display panel enters intothe sustain discharge period C. A negative sustain pulse Psus is appliedto all the sustain electrodes Su1 to Suj between time t12 and time t13,and is applied to all the scanning electrodes Sc1 to Scj between timet14 and time t15. The negative sustain pulse Psus has the pulse heightranging between 170 volts and 200 volts, and the pulse width is 3microseconds. The negative sustain pulse Psus is alternately supplied tothe sustain electrodes Su1 to Suj and the scanning electrodes Sc1 to Scjat time t16, time t17, time t18, . . . , time tx-1 and time tx. Thenegative sustain pulse Psus repeatedly fires the pixels 5 selected inthe write-in discharge period B, and the repetition of firing iscontrolled so as to regulate each pixel 5 to a target brightness. Theion is attracted toward the protective layer 2g during the sustaindischarge period C, and the phosphor layer 1d is never damaged.

After the recovery of the negative sustain pulse Psus to the groundlevel GND at time tx+1, a positive sustain pulse Pend is applied to allthe scanning electrodes Sc1 to Scj between time tx+2 and time tx+3, anda negative erasing pulse Psue- is further applied to the scanningelectrodes Sc1 to Scj between time tx+3 and time tx+4. The positivesustain pulse Pend has the pulse height ranging between 160 volts and200 volts, and the pulse width falls the range from 3 microseconds to 20microseconds. On the other hand, the negative erasing pulse Psue- hasthe pulse height between 50 volts and 100 volts, and the pulse widthranges from 0.5 microsecond to 2 microseconds and, preferably, between0.5 microsecond to 1 microsecond.

The positive sustain pulse Pend first the selected pixels 5, and thenegative e erasing pulse Psue- causes erasing discharge to take place soas to erase the wall charge. However, the non-selected pixels 5 arenever fired in the sustain discharge period C, because the negativesustain pulse Psus, the positive sustain pulse Pend and the negativeerasing pulse Psue- do not cause the potential between the electrodes toexceed the threshold for the discharging.

It is necessary to carefully determine the pulse height of the positivesustain pulse Pend, because the threshold for discharge is variedtogether with the composition of the discharging gas. If the positivesustain pulse Pend has a pulse height large enough to generate thedischarge in non-selected pixels 5, the sustain discharge in thenon-selected pixels 5 decreases the contrast on the display area 6.

FIGS 9A and 9B illustrate the wall charges produced in one of theselected pixels 5 during the sustain discharge period C. Layers andelectrodes of the selected pixel 5 are labeled with the same referencesdesignating the corresponding layers and electrodes of the pixel shownin FIG. 1. In this instance, the dielectric layer 1c and the phosphorlayer 1d as a whole constitute first dielectric structure, and thedielectric layer 2f and the protective layer 2g form in combination asecond dielectric structure.

When the sustain discharge takes place due to the positive sustain pulsePend applied to the scanning electrode 2b, the negative wall charge 20ais accumulated under the scanning electrode 2b, and the positive wallcharge 20b is accumulated under the sustain electrode 2c. The positivewall charge 20c is induced on the first dielectric structure under thescanning electrode 2b as shown in FIG. 9A. The electric force lines 21are directed from the positive wall charges 20b/20c to the negative wallcharge 20a, and the protective layer 2g of magnesium oxide is liable toemit secondary electron due to ion-bombardment.

In this situation, the negative erasing pulse Psue- is superposed on theinternal potential between the scanning electrode 2b and the sustainelectrode 2c due to the wall charges 20a/20b, and causes the erasingdischarge to take place. The erasing discharge erases thenegative/positive wall charges 20a/20b/20c from the first and seconddielectric structure as shown in FIG. 9B. The negative erasing pulsePsue- with the relatively low pulse height erases most of the wallcharges 20a to 20c through the erasing discharge, because the magnesiumoxide layer 2g under the scanning electrode 2b is liable to emit thesecondary electron due to the electric force lines 21.

Moreover, the positive wall charge 20c and the negative erasing pulsePsue- with the low pulse height decrease the negative charge attractedtoward the data electrode 1b, and the negative charge accumulated on thefirst dielectric structure is negligible. Thus only, a negligible amountof negative charge is left over the data electrode 1b, and thecancellation due to the negative charge is ignoreable in the write-indischarge period of the next sub-field. This results in improvement ofthe data write-in characteristics, and the selected pixels 5 are surelyfired without the priming period in the next sub-field.

Finally, the sustain pulse Psus and the erasing Psue- are negative, andthe ion-bombardment on the phosphor layer 1d is negligible. For thisreason, the phosphor layer 1d is never deteriorated, and the duration oflife is prolonged.

Additionally, the positive sustain pulse Pend and the negative erasingpulse Psue- may be applied to the sustain electrodes Sul to Suj as shownin FIG. 10. After the final negative sustain pulse Psus', the positivesustain pulse Pend is applied to all the sustain electrodes Sul to Suj,and the negative erasing pulse Psue- follows.

Second Embodiment

FIG. 11 illustrates another controlling method embodying the presentinvention. The priming discharge period A, the write-in discharge periodB and the sustain discharge period C consitute a sub-field, and thesub-field is repeated with or without the priming discharge period A.The negative priming pulse Pp-, the positive priming pulse Pp+, thenegative erasing pulse Ppe, the negative scanning pulse Pw and thenegative data pulse Pd are supplied to the sustain electrodes Sul toSuj, the scanning electrodes Scl to Scj and the data electrodes Dl to Dkin the priming discharge period A and the write-in discharge period B ina similar manner to those of the first embodiment. For this reason, thepriming discharge period A and the write-in discharge period B are notdescribed hereinbelow.

In the sustain discharge period C, the negative sustain pulse Psus isrepeatedly applied to the sustain electrodes Sul to Suj and the scanningelectrodes Scl to Scj so as to make the selected pixels 5 fired. Thepositive sustain pulse Pend is applied to the scanning electrodes Scl toScj between time t21 and time t22, and a positive erasing pulse Psue+ isapplied to the sustain electrodes Sul to Suj from time t22 to time t23.The positive erasing pulse Psue+ has the pulse height ranging from 50volts to 100 volts, and the pulse width ranges from 0.5 microsecond to 2microseconds and, preferably, between 0.5 microsecond to 1 microsecond.

The positive sustain pulse Psus and the positive erasing pulse Psue+achieve all the advantages of the first embodiment. The positiveelectric charge is accumulated over the data electrodes Dl-Dk associatedwith the selected pixels 5 due to the positive erasing pulse Psue+, andis superposed on the potential between the scanning electrodes Scl-Scjand the data electrodes Dl-Dk in the write-in discharge period B of thenext sub-field. For this reason, the pixels to be fired are selected byusing the scanning pulse Pw with the pulse height lower than that usedin the first embodiment. However, the electric charge is left over thedata electrodes Dl-Dk. The data pulse Pd used in the second embodimentrequires a pulse height larger than that of the first embodiment forovercoming a potential difference due to the electric charge.

In the second embodiment, the positive sustain pulse Pend and thepositive erasing pulse Psue+ are applied to the scanning electrodes Sclto Scj and the sustain electrodes Sul to Suj, respectively. In amodification of the second embodiment, the positive sustain pulse Pendand the positive erasing pulse Psue+ may be applied to the sustainelectrodes Sul to Suj and the scanning electrodes Scl to Scj,respectively.

Third Embodiment

FIG. 12 illustrates yet another controlling method embodying the presentinvention. The priming discharge period A, the write-in discharge periodB and the sustain discharge period C constitute a sub-field, and thesub-field is repeated with or without the priming discharge period A.The negative priming pulse Pp-, the positive priming pulse Pp+, thenegative erasing pulse Ppe, the negative scanning pulse Pw and thenegative data pulse Pd are supplied to the sustain electrodes Sul toSuj, the scanning electrodes Scl to Scj and the data electrodes Dl to Dkin the priming discharge period A and the write-in discharge period B ina similar manner to those of the first embodiment. For this reason, thepriming discharge period A and the write-in discharge period B are notdescribed hereinbelow.

In the sustain discharge period C, the positive sustain pulse Pend isapplied to the scanning electrodes Scl to Scj between time t31 and andtime t32. Thereafter, a positive erasing pulse Psue+ is applied to thesustain electrodes Sul to Suj between time t32 and time t33, and anegative erasing pulse Psue- is further applied to the scanningelectrodes Scl to Scj between time t32 and time t33. The positiveerasing pulse Psue+ and the negative erasing pulse Psue- ranges from 0.5microsecond to 2 microsecond and, preferably between 0.5 microsecond and1 microsecond. The positive erasing pulse Psue+ and the negative erasingpulse Psue- are regulated in such a manner that the total pulse heightfalls within the range between 50 volts and 100 volts.

The positive sustain pulse Pend and the erasing pulses Psue+/Psue-achieve all the advantages of the first and second embodiments. The twokinds of erasing pulses Psue+/Psue- are desirable for controlling theerased state. If the pulse height of the positive erasing pulse Psue+and the pulse height of the negative erasing pulse Psue- areappropriately regulated, the electric charge over the data electrodes dlto Dk are perfectly erased, and the write-in potential in the period Bis made uniform over all the pixels 5.

In a modification of the third embodiment, the positive sustain pulsePend may be applied to the sustain electrodes Sul to Suj after the finalnegative sustain pulse Psus, In this instance, the positive erasingpulse Psue+ and the negative erasing pulse Psue- are concurrentlyapplied to the scanning electrodes Scl to Scj and the sustain electrodesSul to Suj, respectively.

Fourth Embodiment

FIG. 13 illustrates still another controlling method embodying thepresent invention. The priming discharge period A, the write-indischarge period B and the sustain discharge period C constitute asub-field, and the sub-field is repeated with or without the primingdischarge period A. The negative priming pulse Pp-, the positive primingpulse Pp+, the negative erasing pulse Ppe, the negative scanning pulsePw and the negative data pulse Pd are supplied to the sustain electrodesSul to Suj, the scanning electrodes Scl to Scj and the data electrodesDl to Dk in the priming discharge period A and the write-in dischargeperiod B in a similar manner to those of the first embodiment. For thisreason, the priming discharge period A and the write-in discharge periodB are not described hereinbelow.

In the sustain discharge period C, the positive sustain pulse Pend isapplied to the scanning electrodes Scl to Scj between time t41 and timet42. A positive erasing pulse Psue+ is applied to the sustain electrodesSul to Suj between time t42 and time t43. The positive erasing pulsePsue+ has the pulse width ranging from 0.5 microsecond to 2 microsecondsand, preferably, between 0.5 microsecond to 1 microsecond. The pulseheight of the positive erasing pulse Psue+ is dependent on the pulsewidth, and usually ranges from 50 volts to 100 volts.

In order to ensure the erasing, a negative erasing pulse Psue 2 isapplied to the sustain electrodes Sul to Suj between time t43 and timet44, and a negative erasing signal Psue3 is applied to the scanningelectrodes Scl to Scj between time t44 and time t46. The negativeerasing signal Psue3 rapidly goes down from time t44 to time t45, andgradually decreases the gradient from time t45 to time t46. Such a mildwaveform ensures the erasing.

The positive sustain pulse Pend and the positive/negative erasingsignals Psue+/Psue2/Psue3 achieves all the advantages of the thirdembodiment. The negative erasing pulse Psue2 and the negative erasingpulse Psue3 ensure the erasing. In the third embodiment, the positiveerasing pulse Psue+ is applied in synchronism with the negattive erasingpulse Psue-. On the other hand, the three erasing pulses Psue+, Psue2and Psue3 has independent timings, and, for this reason, the fourthembodiment is easier for controlling rather than the third embodiment.

In a modification of the fourth embodiment, the positive sustain pulsePend may be applied to the sustain electrodes Sul to Suj after the finalnegative sustain pulse Psus. In this instance, the positive erasingpulse Psue+ and the negative erasing pulse Psue2 are successivelyapplied to the scanning electrodes Scl to Scj, and the negative erasingsignal Psue3 is applied to the sustain electrodes Sul to Suj.

Fifth Embodiment

FIG. 14 illustrates another controlling method embodying the presentinvention. The priming discharge period A, the write-in discharge periodB and the sustain discharge period C constitute a sub-field, and thesub-field is repeated with or without the priming discharge period A.The negative priming pulse Pp-, the positive priming pulse Pp+, thenegative erasing pulse Ppe, the negative scanning pulse Pw and thenegative data pulse Pd are supplied to the sustain electrodes Sul toSuj, the scanning electrodes Scl to Scj and the data electrodes Dl to Dkin the priming discharge period A and the write-in discharge period B ina similar manner to those of the first embodiment. For this reason, thepriming discharge period A and the write-in discharge period B are notdescribed hereinbelow.

In the sustain discharge period C, the positive sustain pulse Pend isapplied to the scanning electrodes Scl to Scj between time t51 and timet52. A positive erasing pulse Psue+ is applied to the sustain electrodesSul to Suj between time t52 and time t53. The positive erasing pulsePsue+ has the pulse width ranging from 0.5 microsecond to 2 microsecondsand, preferably, between 0.5 microsecond to 1 microsecond. The pulseheight of the positive erasing pulse Psue+ is dependent on the pulsewidth, and usually ranges from 50 volts to 100 volts.

In order to ensure the erasing, a positive erasing pulse Psue2+ isapplied to the scanning electrodes Scl to Scj between time t53 and timet54, and a negative erasing signal Psue3 is applied to the scanningelectrodes Scl to Scj between time t55 and time t56. The negativeerasing signal Psue3 gradually decreases the gradient from time t55 totime t56. Such a mild waveform ensures the erasing.

The positive sustain pulse Pend and the positive/negative erasingsignals Psue+/Psue2+/Psue3 achieves all the advantages of the fourthembodiment. In the fourth embodiment, the second erasing pulse Psue2+ ispositive, and the dielectric structure over the data electrodes layer 1dare lightly charged with the positive charge between bothsustain/screening electrodes and the data electrodes. Thereafter, thenegative erasing signal Psue3 is applied to the scanning electrodes Sclto Scj. The negative erasing signal Psue3 uniformly neutralizes thefirst dielectric structure under both sustain/screening electrodes. Thisresults in a write-in potential lower in pulse height than that of thefourth embodiment.

In a modification of the fifth embodiment, the positive sustain pulsePend may be applied to the sustain electrodes Sul to Suj after the finalnegative sustain pulse Psus. In this instance, the positive erasingpulse Psue+ is applied to the scanning electrodes Scl to Scj, thepositive erasing pulse Psue2+ is applied to the sustain electrodes Sulto Suj, and the negative erasing signal Psue3 is applied to the sustainelectrodes Sul to Suj.

Sixth Embodiment

FIG. 15 illustrates another controlling method embodying the presentinvention. The priming discharge period A, the write-in discharge periodB and the sustain discharge period C constitute a sub-field, and thesub-field is repeated with or without the priming discharge period A.The negative priming pulse Pp-, the positive priming pulse Pp+, thenegative erasing pulse Ppe, the negative scanning pulse Pw and thenegative data pulse Pd are supplied to the sustain electrodes Sul toSuj, the scanning electrodes Scl to Scj and the data electrodes Dl to Dkin the priming discharge period A and the write-in discharge period B ina similar manner to those of the first embodiment. For this reason, thepriming discharge period A and the write-in discharge period B are notdescribed hereinbelow.

In the sustain discharge period C, the positive sustain pulse Pend isapplied to the scanning electrodes Scl to Scj between time t61 and timet62. A negative erasing pulse Psue is applied to the scanning electrodesScl to Scj between time t63 and time t64, and the negative erasing pulsePsue has the pulse width ranging from 0.5 microsecond to 2 microsecondsand, preferably, between 0.5 microsecond to 1 microsecond. The pulseheight of the negative erasing pulse Psue is dependent on the pulsewidth, and usually ranges from 50 volts to 100 volts.

Immediately after the recovery of the negative erasing pulse Psue, anegative erasing pulse Psue2 is applied to the sustain electrodes Sul toSuj between time t64 and time 65, and a negative erasing signal Psue3 isapplied to the scanning electrodes Scl to Scj between time t66 and timet67. The negative erasing signal Psue3 gradually decreases the gradientfrom time t66 to time t67 as similar to the fifth embodiment, and themild waveform ensures the erasing.

The positive sustain pulse Pend and the negative erasing signalsPsue/Psue2/Psue3 achieves all the advantages of the fourth embodiment.In the sixth embodiment, all the erasing signals Psue/Psue2/Psue3 arenegative. The positive sustain pulse Pend has a relatively large pulseheight, and the pulse width is equal to or greater than 10 microseconds.The insulating structure over the data electrodes Dl to Dk accumulatesthe positive charge over the data electrodes Dl to Dk, and the threenegative erasing signals Psue/Psue2/Psue3 erases the positive chargesfrom the insulating structure over the data electrodes Dl to Dk.

In a modification of the sixth embodiment, the positive sustain pulsePend may be applied to the sustain electrodes Sul to Suj after the finalnegative sustain pulse Psus. In this instance, the negative erasingpulse Psue is applied to the sustain electrodes Sul to Suj, the negativeerasing pulse Psue2 is applied to the scanning electrodes Scl to Scj,and the negative erasing signal Psue3 is applied to the sustainelectrodes Sul to Suj.

Seventh Embodiment

FIG. 16 illustrates another controlling method embodying the presentinvention. The controlling method implementing the seventh embodiment issimilar to the controlling method shown in FIG. 8 except for a positiveprotective bias pulse Pdb. The positive sustain pulse Pend is applied tothe scanning electrodes Scl to Scj from time t71 to time t72, and thepositive protective bias pulse Pdb is also applied to the dataelectrodes between time t71 and time t72. The positive protective biaspulse Pdb has a pulse height less than the threshold for dischargebetween the sustain electrodes Sul to Suj and the data electrodes Dl toDk, and the potential difference between the scanning electrodes Scl-Scjand the data electrodes Dl-Dk is less than the threshold for thedischarge therebetween. Thus, the positive protective bias pulse Pdbprevents the non-selected pixels 5 from undesirable misfiring. Thenegative erasing pulse Psue- is applied to the scanning electrodes Sclto Scj between time t72 and time t73, and erases the wall charges fromthe first dielectric structure and the second dielectric structure. Thenegative erasing pulse Psue- has a pulse width ranging from 0.5microsecond to 2 microseconds and, preferably, between 0.5 microsecondand 1 microsecond.

The positive sustain pulse Pend and the negative erasing pulse Psue-achieves all the advantages of the first embodiment, and the positiveprotective bias pulse Pdb does not allow the positive sustain pulse Pendto fire the non-selected pixels 5, and improves the contrast of an imageproduced on the display area 6.

Eighth Embodiment

FIG. 17 illustrates another controlling method embodying the presentinvention. The controlling method implementing the eighth embodiment issimilar to the controlling method shown in FIG. 8 except forpositive/negative sustain pulses Pend+/Pend-. The positive sustain pulsePend+ is applied to the scanning electrodes Scl to Scj from time t81 totime t82, and the negative sustain pulse Pend- is applied to the sustainelectrodes Sul to Suj in synchronism with the positive sustain pulsePend+. The positive sustain pulse Pend+ has a pulse height less than thethreshold for the discharge between the scanning electrodes Scl-Scj andthe data electrodes Dl-Dk, and the negative sustain pulse Pend- has apulse height less than the threshold for the discharge between thesustain electrodes Sul-Suj and the data electrodes Dl-Dk. The sum of thepositive sustain pulse Pend+ and the negative sustain pulse Pend- isless than the threshold for the discharge between the sustain electrodesSul-Suj and the scanning electrodes Scl-Scj and is equal to or greaterthan the minimum sustain potential between the scanning electrodesScl-Scj and the sustain electrodes Sul-Suj.

Subsequently, the negative erasing pulse Psue- is applied to thescanning electrodes Scl to Scj between time t82 and time t83, and erasesthe wall charges from the first dielectric structure and the seconddielectric structure.

In this instance, the positive sustain pulse Pend of the firstembodiment is split into the positive sustain pulse Pend+ and thenegative sustain pulse Pend-, and the positive sustain pulse Pend+ andthe negative sustain pulse Pend- prevent the non-selected pixels 5 frommisfiring, and improves the contrast of an image produced on the displayarea 6.

A modification of the eighth embodiment, the positive sustain pulsePend+ and the negative erasing pulse Psue- may be applied to the sustainelectrodes Sul to Suj after the final negative sustain pulse Psus. Inthe modification, the negative sustain pulse Pend- is applied to thescanning electrodes Scl-Scj in synchronism with the positive sustainpulse Pend+.

As will be appreciated from the foregoing description, only the finalsustain pulse Pend is positive with respect to the potential level onthe data electrodes Dl-Dk in accordance with the present invention, andallows the erasing pulse to effectively erase the wall charges from thefirst/second dielectric structure without sacrifice of the durability ofthe phosphor layer 1d.

Although particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art thatvarious changes and modifications may be made without departing from thespirit and scope of the present invention.

For example, if the positive erasing pulse Psue+ and the negativeerasing pulse Psue2 achieve good erased state, the negative erasingsignal Psue3 would be skipped in the fourth, fifth and sixthembodiments.

The erasing pulse Psue- used in the seventh/eighth embodiment may bechanged to the erasing pulse or pulses used in any one of the second tosixth embodiment.

In the first to eight embodiments, the pulses go up or go down from theground level. However, if the pulses are established in the relativerelation described hereinbefore, the pulses may be changed from acertain positive potential level or a certain negative potential level.

The pulse height and the pulse width described hereinbefore inconnection with the first to eighth embodiments are changeable dependingupon the plasma display panel to which the present invention appertains.

What is claimed is:
 1. A method of controlling an alternating currentplasma display panel including a plurality of data electrodes coveredwith a first dielectric structure, a plurality of scanning electrodescovered with a second dielectric structure spaced from said firstdielectric structure for forming a space filled with discharging gas anda plurality of sustain electrodes covered with said second dielectricstructure and respectively paired with said plurality of scanningelectrodes for forming a plurality of electrode pairs, each of saidplurality of data electrodes and each of said plurality of electrodepairs defining one of a plurality of pixels selectively fired,saidmethod comprising the steps ofa) applying a scanning pulse sequentiallyto said plurality of scanning electrodes and a data pulse selectively tosaid plurality of data electrodes so as to create a first internalpotential available for firing in certain pixeles selected from saidplurality of pixels, and b) alternately applying a first sustain pulsenegative with respect to a potential level on said plurality of dataelectrodes to said plurality of sustain electrodes and said plurality ofscanning electrodes so as to make said certain pixels fired, c) applyinga second sustain pulse positive with respect to said potential level onsaid plurality of data electrodes to either sustain or scanningelectrodes so as to accumulate wall charges on said first insulatingstructure and said second insulating structure for creating a secondinternal potential expressed by a first electric force line directedfrom said first insulating structure to said second insulating structureand a second electric force line between a first area of said secondinsulating structure adjacent to said plurality of scanning electrodesand a second area of said second insulating structure adjacent to saidplurality of sustain electrodes, and d) erasing said wall charges fromsaid first insulating structure and said second insulating structure,and in which a first erasing pulse is applied to either sustain orscanning electrodes.
 2. The method as set forth in claim 1, in whichsaid first erasing pulse is negative with respect to said potentiallevel on said plurality of data electrodes, and is applied to saideither sustain or scanning electrodes applied with said second sustainpulse in said step c).
 3. The method as set forth in claim 1, in whichsaid first erasing pulse is positive with respect to said potentiallevel on said plurality of data electrodes, and is applied to saideither sustain or scanning electrodes in said step d) opposite to saideither sustain or scanning electrodes in said step c).
 4. The method asset forth in claim 1, in which said first erasing pulse is applied tosaid either sustain or scanning electrodes in said step d) identicalwith said either sustain or scanning electrodes in said step c), and asecond erasing pulse is applied to either sustain or scanning electrodesopposite to said either sustain or scanning electrodes in said step c).5. The method as set forth in claim 4, in which said first erasing pulseis negative with respect to said potential level on said plurality ofdata electrodes, and said second erasing pulse is positive with respectto said potential level on said plurality of data electrodes.
 6. Themethod as set forth in claim 5, in which said first erasing pulse issynchronous with said second erasing pulse.
 7. The method as set forthin claim 5, in which said first erasing pulse is applied after saidsecond erasing pulse.
 8. The method as set forth in claim 7, in which athird erasing pulse is applied to said either sustain or scanningelectrodes applied with said second erasing pulse between said seconderasing pulse and said first erasing pulse, and is negative with respectto said potential level on said plurality of data electrodes.
 9. Themethod as set forth in claim 8, in which said first erasing pulsegradually decreases a pulse height thereof with time.
 10. The method asset forth in claim 7, in which a third erasing pulse is applied to saideither sustain or scanning electrodes applied with said first erasingpulse before said second erasing pulse and said first erasing pulse, andis positive with respect to said potential level on said plurality ofdata electrodes.
 11. The method as set forth in claim 4, in which saidfirst erasing pulse and said second erasing pulse are negative withrespect to said potential level on said plurality of data electrodes,and a third erasing pulse is applied to said either sustain or scanningelectrodes applied with said first erasing pulse between said seconderasing pulse and said first erasing pulse.
 12. The method as set forthin claim 11, in which said first erasing pulse gradually decreases apulse height thereof with time.
 13. The method as set forth in claim 2,in which a protective bias pulse is applied to said plurality of dataelectrodes in synchronism with said second sustain pulse so as toprevent the others of said plurality of pixels except for said certainpixels from misfiring.
 14. The method as set forth in claim 13, in whichsaid protective bias pulse is positive with respect to said potentiallevel on said plurality of data electrodes in said step b).
 15. Themethod as set forth in claim 14, in which said protective bias pulsemakes a potential difference between said plurality of sustainelectrodes and said plurality of data electrodes and a potentialdifference between said plurality of scanning electrodes and saidplurality of data electrodes less than thresholds for dischargingtherebetween.
 16. The method as set forth in claim 1, in which a thirdsustain pulse is applied to either sustain or scanning electrodesopposite to said either sustain or scanning electrodes in said step c)in synchronism with said second sustain pulse, and is negative withrespect to said potential level on said plurality of data electrodes forpreventing remaining pixels except for said certain pixels frommisfiring.
 17. The method as sest forth in claim 1, further comprisingthe step of carrying out a priming discharge before said step a). 18.The method according to claim 1, wherein the erasing pulse is applied toonly said sustain electrode or only to said scanning electrodes.
 19. Themethod according to claim 2, wherein the erasing pulse has a smallerheight relative to a sustain pulse and wherein the erasing pulse isapplied to only said sustain electrode or only to said scanningelectrodes.
 20. The method according to claim 17, wherein the erasingpulse is applied to only said sustain electrode or only to said scanningelectrodes.